Trace element analysis of size classified aerosol particles C. Lüdke, E. Hoffmann, J. Skole, *M. Kriews Institute for Spectrochemistry and Applied Spectroscopy *Alfred Wegener Institute for Polar- and Marine Research
Introduction Sampling with the cascade impactor Measurements by SEM – EDXA Measurements by ETV-ICP-MS Catalyst borne elements in Berlin air Air borne elements over the Atlantic Ocean Conclusion
XXXII CSI, Pretoria, South Africa Atmospheric particles
Natural sources: volcanism mineral dust biomass burning sea spray Composition: Na, Mg, K, Sr, Si, Al, Ca, Fe, Ti, S, Mn, Ba... Anthropogenic sources: power plant waste incineration industrial processes transportation Composition: Be, Cd, Hg, Mo, Ni, Sb, Se, As, Sn, V, Cr, Cu, C, Pb, Pt...
XXXII CSI, Pretoria, South Africa Atmospheric particles The composition of aerosol particles is determined by the course of chemical and physical reactions occurring in particle generation and transportation.
Required monitoring: Relevant sources, Deposition, Atmospheric monitorig Effect on man and environment,
Measurable property: Chemical composition, Shape Number of particles, Size distribution
XXXII CSI, Pretoria, South Africa Cascade Impactor Air in G ' 9 η 6 W D H = 8 × & ρ
Nozzles plate dæ : 16.5 µm .....0.35 µm
D Stage 1 U aerodynamic diameter Impaction plate D : 2.7 mm ...... 0.35 mm
D diameter of the orifice Stage 2 target U : 48.0 cm/s ... 7057 cm/s lineare gas velocity D : gas viscosity Stage N St : Stokes number C : Cunningham factor Back-up filter : particle density
to vacuum pump, controlled flow rate 2.2 m³/h
XXXII CSI, Pretoria, South Africa SEM picture of a graphite target with impacted particulates
XXXII CSI, Pretoria, South Africa Experimental set-up for ETV-ICP-MS
Fixing slits Impaction area Particulates Injection hole
Graphite target Graphite tube container
Elan 5000 ICP torch Electrothermal vaporizer Lid
Quadrupole Ion lenses
Turbo Turbo RF pump pump supply
Pump Pump Target Pivot System computer Plasma Auxiliary Stabilization XXXII CSI, Pretograias, South Africgaas gas Limits of detection, based on the 3 criteria
Measured 55Mn 59Co 105Pd 107Ag 111Cd 118Sn isotope LOD pg/m³ 1 0.8 0.2 0.03 0.2 0.5
Measured 121Sb 130Rh 140Ce 195Pt 205Tl 208Pb isotope
LOD pg/m³ 1 0.1 3 0.6 0.05 0.2
XXXII CSI, Pretoria, South Africa Sampling conditions: Location: 40 km north-west of town centre, 4 m above ground; Time: 76 h; Volume: 0.93 m³ per target
XXXII CSI, Pretoria, South Africa Platinum group elements in Berlin air correlated to Ce
pg/m3 100
10 &H
1 3G 3W
0.1 5K
0.01 0.1 1 10 100 Aerodyn. diameter / µm
XXXII CSI, Pretoria, South Africa Mean concentration of platin group elements in Berlin air
Element content Correlation Maximum (sum over all diameters) coefficient in particle pg/m³ distribution
140 103 105 195 140 195 Isotope Ce Rh Pd Pt Ce : Pt all
Plume of Berlin 250 + 25 4 + 1 8 + 1 7 + 1 0.903 3 - 5µm
Motorway tunnel 1140 + 100 28 + 5 16 + 2 35 + 6 0.899 7 µm
XXXII CSI, Pretoria, South Africa Satellite picture of Sahara dust
Ref.: Der Spiegel Nr. 50 Dec. 11, 2000 XXXII CSI, Pretoria, South Africa Research vessel „Polarstern“
XXXII CSI, Pretoria, South Africa On board sampling station
Sampling conditions: Daily aerosol sampling, 22 m above sea level Time: 23 h Air volume: 0.3 m³ per target
XXXII CSI, Pretoria, South Africa Polarstern Cruise ANT XVII/1 (Bremerhaven-Las Palmas-Cape Town, Dec. 14, 1999 till Jan. 06, 2000
XXXII CSI, Pretoria, South Africa Particles of the 1.1 µm stage (site of sampling: the British Channel)
Philips XL 30 ESEM
XXXII CSI, Pretoria, South Africa SEM-EDX analysis
XXXII CSI, Pretoria, South Africa Particles of the 3.5 µm stage site of sampling 14°N (Sahara dust)
XXXII CSI, Pretoria, South Africa SEM-EDX analysis
XXXII CSI, Pretoria, South Africa Mn
Manganese >SJPñ@
5000 4000 3000 2000 /DWLWXGH 1000 1RUWK 0 0 5 10 15 20
$HURG\QDPLFGLDPHWHU>P@
XXXII CSI, Pretoria, South Africa
Pb
Lead >SJPñ@
6000 5000 4000 3000 2000 /DWLWXGH 1RUWK 1000 0 0 5 10 15 20
$HURG\QDPLFGLDPHWHU>P@
XXXII CSI, Pretoria, South Africa
Sb
Antimony >SJPñ@
250 200 150 100 /DWLWXGH 50 1RUWK 0 0 5 10 15 20
$HURG\QDPLFGLDPHWHU>P@
XXXII CSI, Pretoria, South Africa
Spatial distribution of element concentrations in aerosol over the Atlantic Ocean
In &RQWHQWSJP Ag &RQWHQWSJP 10000 100000
10000 1000 Sn 1000 In 100 10000 100
1000 10 Cs Ag
10 1 60 40 20 0 -20 -40 60 40 20 0 -20 -40 /DWLWXGH1RUWK /DWLWXGH1RUWK
XXXII CSI, Pretoria, South Africa Mean element concentration in aerosol (pg / m³)
Element North Atlantic Region of South Atlantic Sahara dust 52°N - 22°N 22°N – 6°N 6°N – 31°S Ag 580 ± 130 220 ± 50 270 ± 50 Sb 1100 ± 290 300 ± 25 260 ± 60 Tl 28 ± 4 78 ± 20 16 ± 3 Sn 3950 ± 860 20800 ± 5100 1970 ± 470 Mn 3600 ± 870 15000 ± 2000 2480 ± 550 Pb 18200 ± 2800 18900 ± 1800 13600 ± 2600 Cs 21 ± 9 215 ± 65 21 ± 7 In 920 ± 300 520 ± 150 940 ± 300 Bi 250 ± 40 450 ± 50 200 ± 30
XXXII CSI, Pretoria, South Africa Conclusion
• Size classified sampling of aerosol particles on separate graphite targets and subsequent multielement analysis is a useful tool for the characterization of aerosol particles.
• The high efficiency of the sampling system combined with the powerful analytical technique permits the study of isotope correlations allowing the identification of particle sources as well as transport and deposition processes.
XXXII CSI, Pretoria, South Africa Acknowledgement
· Kerstin Taubner (ISAS) for sample preparation and measurements.
· Thomas Adam and Ute Bock (AWI) for assistance in SEM operation and EDX analysis
· the crew of R. V. Polarstern for their help in setting up our instruments and providing logistical support.
· the DFG for the financial support.
XXXII CSI, Pretoria, South Africa XXXII CSI, Pretoria, South Africa